Locking differentials typically include a gear case defining a gear chamber, and disposed therein, a differential gear set including at least one input pinion gear, and a pair of output side gears. A clutch pack can be disposed between at least one of the side gears and an adjacent surface of the gear case so that the clutch pack can prevent relative rotation between the gear case and the one side gear. Clutch packs are preferable to dog clutches because clutch packs tend to absorb energy more effectively and have a higher engagement speed and smoother engagement action while protecting the differential and driveline components from high impact loading. Cam members may be disposed between the clutch pack and an adjacent side gear to engage the clutch pack upon relative rotation of the cam members. In one type of locking differential, the cam member ramps in response to engage the clutch pack, thus locking the side gear relative to the differential gear case.
Many differential systems have an actuating mechanism to move the clutch pack to its engaged condition. Conventional systems engage the clutch pack in response to a sensed predetermined speed differential between wheels. Alternative systems may include an actuator that engages the clutch packs in response to an electrical signal instead of a sensed speed difference. Some possible actuators include piston-cylinder actuators or electromagnetic systems that require multiple coils within the differential case. These systems are complex and increase the total number of parts in the differential.
Mechanical locking differentials are still often used in vehicles, but there are sometimes concerns regarding the compatibility between such differentials and anti-lock braking systems or electronic stability control systems. However, replacing the mechanical locking differential with a currently-known electronically triggered differential design would be unduly complicated and potentially cost-prohibitive.
There is a desire for an electronically triggered locking differential with a simple, cost-effective design. There is also a desire for an electronically triggered locking differential that can be easily adapted to currently-known mechanical locking differentials to simply conversion to an electronically triggered differential.